Successful use of eculizumab in a pediatric patient treated for paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, debilitating life-threatening clonal hematopoietic stem cell disease. The clinical manifestations of PNH are usually seen in adulthood and are very rarely reported in children. Eculizumab, a humanized monoclonal antibody targeting and preventing cleavage of the terminal complement protein C5, has become the "gold standard" of treatment for hemolysis or significant disease-related complications in patients with PNH. Although eculizumab is not licensed for use in pediatrics, we report a young PNH patient with bone marrow failure and severe episodes of hemolytic anemia who was treated successfully with eculizumab for >18 months.